This sentiment was echoed by Morris Travers, with whom Ramsay co-discovered the four noble gases—neon, argon, krypton, and xenon. “The blaze of crimson light from the tube told its own story ...

Xenon's discovery concluded an intense period of research on noble gases. Much heavier than neon and krypton, it had not been explicitly predicted, and was sufficiently rare to avoid chance detection.